Establishment of a new breeding procedure based on rice gene targeting using information of molecular genetics and attempt to generate a new variety.

为了利用基因打靶技术(GT)培育水稻新品种，采用基因打靶(GT)技术对Osrac1进行了基因改造，获得了抗稻瘟病的水稻品种。由于Osrac1中的G19V替换在随机转基因水稻中显示了有效的免疫力，因此对原始Osrac1基因进行了相同的修改。在GT进行G19V替换后，通过Cre-loxP介导的无标记系统去除了Osrac1基因座位上残留的阳性标记。在外显子1的G到T交替的分离纯合系的转基因水稻植株中检测到Osrac1的激活，然而，植株中意外的生长抑制也是相关的。获得了16个携带PvACR的水稻植株株系，用于水稻抗砷育种。

For generation of a rice new variety by gene targeting (GT) procedure, the OsRac1 was modified by GT based on positive-negative selection to generate blast fungus resistance rice. Since the G19V substitution in OsRac1 had shown the effective immunity in random transgenic rice, the same modification at the original OsRac1 locus was examined. Following to GT for G19V substitution positive-marker remained in the OsRac1 locus was removed by Cre-loxP mediated marker free system. The OsRac1 activation was detected in the gene-modified rice plants of segregated homozygous lines for the G to T alternation in the exon 1, however, unexpected growth inhibition in the plants was also associated. For generation of arsenic resistant rice, the 16 of rice plant lines having PvACR were obtained.